High density polyethylene thermal recycling

N.K. Madi, Thermal and mechanical properties of injection molded recycled high density polyethylene blends with virgin isotactic polypropylene. Mater. Des. 46, 435-441 (2013)... 

A laser flash technique has been used to determine the diffusivity of pyroelectric polymers such as polyvinylidene fluoride [83], whereas hot-wire techniques have been used to determine the thermal diffusivity of high-density polyethylene, low-density polyethylene propylene, and polystyrene [83], Dos Santos and coworkers [84] utilized the laser flash technique to study the effect of recycling on the thermal properties of selected polymers. Thermal diffusivity expresses how fast heat propagates across a bulk material, and thermal conductivity determines the woiking temperature levels of a material. Hence, it is possible to assert that those properties are important if a polymer is used as an insulator, and also if it is used in applications in which heat transfer is desirable. Five sets of virgin and recycled commercial polymers widely used in many applications (including food wrapping) were selected for this study. 

Automotive industry waste provided another idea for a study [10]. Recycled plastics from bumpers are being applied in several areas, even as new bumpers [11, 12]. Thermal analysis was applied to the material used in discarded car bumpers, which came from standard grade automobiles of different brands. The recycled polymer composition was a polymeric blend of PP, ethylene-propylene-diene monomer (EPDM) and high-density polyethylene (HOPE). Differential scanning calorimetry (DSC) analysis (Figure 2.5) confirmed the presence of PP, and indicated HDPE and EPDM as ingredients in the formulation of car bumpers. 

A study was made of the effects of addition of recycled polypropylene on the incompatible blends of virgin polypropylene with high-density polyethylene. The characteristics of the recycled polypropylene were determined by spectrographic and thermal analysis means. The mechanical properties of the blends were determined. The 50/50 blend of the two virgin polymers benefited most from the addition of the recycled polypropylene. 9 refs. BRAZIL USA... 

Cellulose materials are good candidates to use as fillers in polymers, especially with their recent importance in recycling. There are many different types of materials available, such as wood flour, recycled newspaper, nut shells, and starch. These materials have several advantages, including low cost, low density, low abrasiveness, and they are a renewable resource. However, they do have a number of disadvantages, such as low thermal stability, high moisture absorption, and poor interfacial adhesion. Despite these problems, there are a number of products available in the marketplace. One of the most visible is plastic lumber. Most plastic lumber is made using polyethylene as the base resin and contains up to 50% wood. Much of the time, both resin and wood feedstocks come from recy-... 

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